1. Field of the Invention
The present invention relates to a package structure, and more particularly to a chip module package structure.
2. Related Art
With the rapid development and advancement of the electronic industry, various electronic products have been widely applied in daily lives, and provide more diversified functional options for users. The functional options of the electronic products usually need to be achieved by peripheral input devices (for example, a mouse, a keyboard, and a remote controller) of the electronic products.
For example, in a computer system, instructions are usually input and operated by using a mouse device. Generally, mice can be approximately categorized into two types, namely, mechanical and optical mice. A mechanical mouse mainly utilizes rotation of a trackball disposed at a bottom thereof to drive a sensing element in the mouse, so as to calculate a moving distance of the mouse. However, during rotation, the trackball is easily abraded due to an operation plane (for example, a table top or mouse pad) on which the mouse is placed, and easily carries impurities such as dust and cotton flock on the operation plane into the mouse, resulting in that the accuracy of the mechanical mouse is easily degraded after a long time of use.
An optical mouse is based on optics principles, in which an optical source irradiates a surface, a beam reflected back is picked up within a certain period of time, and by means of rapid scan and pickup, a moving direction and a moving distance of the optical mouse are calculated through comparison. The optical mouse replaces the trackball with the optical technique, so as to solve the problem that the trackball of the mechanical mouse is easily abraded and impurities easily accumulate in the mechanical mouse. Generally, in terms of structural configuration, the optical mouse mainly includes an upper housing and a lower housing, and a lens assembly and a circuit board are disposed in an accommodation space formed by the upper housing and the lower housing. The lens assembly is disposed on the lower housing, a light emitting diode (LED) and a sensor are inserted on the circuit board, and bottom sides of the LED and the sensor are corresponding to the lens assembly. In use, a light ray signal emitted by the LED emits passes through a first lens of the lens assembly, and is refracted to a surface (for example, a table top) by a reflecting mirror, reflected to a second lens of the lens assembly by the surface, and then received by the sensor.
However, in the main structure of the conventional optical mouse, since the LED and the sensor need to be respectively disposed on the circuit board, and relative positions of the LED and the sensor need to be accurately adjusted accordingly, the assembly time required for the conventional optical mouse is rather long, resulting in an excessive manufacturing and production cost.